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Volume Rendering Issue

PostPosted: Fri Mar 15, 2019 3:22 pm
by tobywe
I have an issue every time I try to render volumes with Octane, the same issue with both Octane 4 latest build and 2018.1.

When I interactively change some of the settings on the volume shader, the IPR updates to what looks to be the correct changes that I would expect, but then when I refresh the IPR it changes back to a much higher density. It also renders the much darker/denser volume. The step length seems to have the biggest affect on it, but I'm finding it incredibly difficult to get any reliable sense of how it will come out by changing the parameters without being able to see interactively how it will look once refreshed.

I hope this makes sense and I've attached images to try and illustrate the issue. Since nobody else has posted about this on the forums, I imagine it must just be something I'm doing, but I have tried at different points with different scenes in the last couple of months to get it working, without any luck. I'm also attaching a test scene, in case there's anything obvious in there that I'm doing wrong.

If you are able to take a look, that would be amazing!

Many thanks

Toby


interactive.PNG


render.PNG

Re: Volume Rendering Issue

PostPosted: Fri Mar 15, 2019 5:35 pm
by tobywe
I think the file didn't attach, so I've zipped it and attached it now, in case there are any clues in the scene

Re: Volume Rendering Issue

PostPosted: Mon Mar 18, 2019 10:47 pm
by juanjgon
Hi,

Sorry, I've been trying to reproduce this problem here, but without luck so far. The volume rendering is always the same after changing any parameter, after reloading the scene in the IPR or after rendering to disk. Are you using the latest 2018.1.0.7 or 4.02.1.0 plugin builds?

Thanks,
-Juanjo

Re: Volume Rendering Issue

PostPosted: Tue Mar 19, 2019 10:56 am
by labmeta
Actually i've recently noticed this behaviour over the last few days as well on the 2018.1.0.6 Build.

It was a bit inconsistent, but it seemed that the IPR was picking up changes to the volume shader with a large lag.

Re: Volume Rendering Issue

PostPosted: Tue Mar 19, 2019 5:17 pm
by tobywe
Thanks for having a look at it and I'll do some extra digging to see if I can find any clues as to what might be causing it. I exported the the scene and opened it in the Octane standalone and it seemed to work fine there. Really strange!

Re: Volume Rendering Issue

PostPosted: Tue Mar 19, 2019 5:20 pm
by tobywe
Oh and yes, I've been using the latest plugins. What's strange is that I've had the same behaviour since trying to do some work with volumes last December (ie with earlier plugins), which is why I imagined it might be something my end as someone else would've reported it by now if it were a bug.

Re: Volume Rendering Issue

PostPosted: Wed Mar 20, 2019 7:16 am
by tobywe
Just uploading a video for reference, too. I've been going slightly mad trying to sort it as I can't work out any clues as to what it could be.

In the scene is a simple sphere with a cloud volume node attached and a bit of noise to break it up (I tried playing with density values at sop level, with no luck). There's a single area light and no environment, with the ipr on path tracing and the other render target parameters at their default. I'm using Octane 2018.1.0.6 and Houdini 17.0.416 but, as I mentioned, it seems to be consistent with results that I have been getting with other versions of Octane, including the latest Octane 4. Also, when importing into the standalone, it seems to work ok.

If you have any ideas I might be able to try out then I'd be really grateful. I've attached the scene file that's stripped back to just this cloud sphere, in case it might help replicate it.

Many thanks,

Toby

Re: Volume Rendering Issue

PostPosted: Tue May 21, 2019 9:19 pm
by juanjgon
Sorry for the late reply. Finally, I've been able to reproduce this problem here, and it seems related to the material set at the SOP level. If you set the material in the OBJ node, all seems to work fine. I've not found why this weird issue happens yet, but I'm investigating it ...

Thanks for your patience,
-Juanjo

Re: Volume Rendering Issue

PostPosted: Tue May 28, 2019 6:22 pm
by juanjgon
I've found the problem. It will be fixed in the plugin build. As I have said, the workaround is to set the volume material at the OBJ level.

Thanks for reporting this issue!
-Juanjo